A Research Resource entitled Center for Gamma-Ray Imaging is proposed. The overall objective of this Resource is to develop new gamma-ray imaging instruments with dramatically improved spatial and temporal resolution and to make them available to a wide community of biomedical and clinical researchers. Three different high-resolution SPECT (single-photon emission computed tomography) systems for animal imaging will be developed. First, an exiting system called FASTSPECT will be modified for user as a general-purpose animal SPECT system with 2-3 mm spatial resolution, depending on the field of view. Then a dedicated system for small rodents and low-energy radiotracers will be build, with a design goal of 1 mm spatial resolution. The third system will allow imaging of mice at higher energy, and here the goals are 0.5 mm resolution and the ability to image a mouse heart beating at 600 bpm. In addition, an ultrahigh-resolution spot imager based on a new concept called the synthetic collimator will be developed, and new methods of tumor detection with surgical probes with be investigated. The collaborative research proposed here will apply these new imaging tools to basic research in functional genomics, cardiovascular disease and cognitive neuroscience and to clinical research in breast cancer and surgical tumor detection. The Resource will also make contributions to the emerging science of lf image-quality assessment. Training in the use of these unique imagers will be conducted at several locations, and an animal-imaging facility and a detector design and calibration facility will will be established for service to the biomedical research community. Results of the resource will be disseminated by innovative uses of the Internet as well as through traditional scientific publishing.